WOLFRAM SYSTEM MODELER
Scenario_4More accessible non-recoverable natural resources, pollution control, and land yield enhancement |
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Diagram
Wolfram Language
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SystemModel["SystemDynamics.WorldDynamics.World3.Scenario_4"]
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Information
This is Scenario #4 of the WORLD3 model. This scenario starts out with the same assumptions as Scenario #3. Improvements in pollution control technology have led to an increase in the population. There are additional mouths to be fed, but unfortunately, not enough food is being grown to feed the population in the long run. The population stagnates, and there is massive hunger in the world.
In this new scenario, it is thus postulated that additional efforts are being undertaken to increase the yield of food per hectare of arable land.
References:
- Meadows, D.H., D.L. Meadows, J. Randers, and W.W. Behrens III (1972), Limits to Growth: A Report for the Club of Rome's Project on the Predicament of Mankind, Universe Books, New York, 205p.
- Meadows, D.L., W.W. Behrens III, D.M., Meadows, R.F. Naill, J. Randers, and E.K.O. Zahn (1974), Dynamics of Growth in a Finite World, Wright-Allen Press, 637p.
- Meadows, D.H., D.L. Meadows, and J. Randers (1992), Beyond the Limits, Chelsea Green, 300p.
- Meadows, D.H., J. Randers, and D.L. Meadows (2004), Limits to Growth: The 30-Year Update, Chelsea Green, 368p.
In order to accomplish this change, you need to modify the table P_Yield_Tech_Chg_Mlt_LYCM that models a multiplier to the investment in technology to improve land yield:
parameter Real p_yield_tech_chg_mlt[:] = {0,0,0.04,0.04} "Yield technology change multiplier";.
Simulate the model from 1900 until 2100, and display the same variables as in the book Limits to Growth: The 30-Year Update at page 215:
The results obtained are visibly different from those shown in the book Limits to Growth: The 30-Year Update primarily due to the quantization error.
In this model, some of the gains are huge. For example, the variable agr_inp_per_hect, i.e., the investment in agricultural production per hectare of arable land, that in earlier scenarios assumed values in the range [2,30] dollars per hectare and year suddenly assumes values of several thousands of dollars per hectare and year. We observe hyperinflation at work.
Due to the amplified quantization errors, the collapse happens more than 20 years earlier than shown in the book. If we were to simulate beyond the year 2100, the results obtained using the Modelica implementation could be considered similar to those obtained using STELLA. The trajectories simply get shifted in time. However, since we stop the simulation in 2100, our results look qualitatively different.
Parameters (77)
| agr_mtl_toxic_index |
Value: 1 Type: Real (1/dollar) Description: Agricultural materials toxicity index |
|---|---|
| assim_half_life_1970 |
Value: 1.5 Type: Real (yr) Description: Pollution assimilation half life in 1970 |
| avg_life_land_norm |
Value: 1000 Type: Real (yr) Description: Normal life span of land |
| des_compl_fam_size_norm |
Value: 3.8 Type: Real Description: Desired normal complete family size |
| des_food_ratio_dfr |
Value: 2 Type: Real Description: Desired food ratio |
| des_ppoll_index_DPOLX |
Value: 1.2 Type: Real Description: Desired persistent pollution index |
| des_res_use_rt_DNRUR |
Value: 4800000000.0 Type: Real (ton/yr) Description: Desired resource utilization rate |
| food_short_perc_del |
Value: 2 Type: Real (yr) Description: Food shortage perception delay |
| fr_agr_inp_pers_mtl |
Value: 0.001 Type: Real Description: Effective fraction of agricultural pollution input |
| frac_res_pers_mtl |
Value: 0.02 Type: Real Description: Effective fraction of resource utilization on pollution generation |
| hlth_serv_impact_del |
Value: 20 Type: Real (yr) Description: Health service impact delay |
| income_expect_avg_time |
Value: 3 Type: Real (yr) Description: Income expected average time |
| ind_mtl_emiss_fact |
Value: 0.1 Type: Real (1/ton) Description: Industrial materials emission factor |
| ind_mtl_toxic_index |
Value: 10.0 Type: Real Description: Industrial materials toxicity index |
| ind_out_pc_des |
Value: 400 Type: Real (dollar/yr) Description: Desired annual industrial per capita output |
| ind_out_in_1970 |
Value: 790000000000.0 Type: Real (dollar/yr) Description: Industrial output in 1970 |
| inherent_land_fert |
Value: 600 Type: Real (kg/(hectare.yr)) Description: Inherent land fertility |
| labor_force_partic |
Value: 0.75 Type: Real Description: Percentage of participating labor force |
| labor_util_fr_del_time |
Value: 2 Type: Real (yr) Description: Labor utilization fraction delay time |
| land_fr_harvested |
Value: 0.7 Type: Real Description: Land fraction harvested |
| life_expect_norm |
Value: 28 Type: Real (yr) Description: Normal life expectancy |
| lifet_perc_del |
Value: 20 Type: Real (yr) Description: Perceived life-time delay |
| max_tot_fert_norm |
Value: 12 Type: Real Description: Normal maximal total fertility |
| p_avg_life_agr_inp_1 |
Value: 2 Type: Real (yr) Description: Default average life of agricultural input |
| p_avg_life_agr_inp_2 |
Value: 2 Type: Real (yr) Description: Controlled average life of agricultural input |
| p_avg_life_ind_cap_1 |
Value: 14 Type: Real (yr) Description: Default average life of industrial capital |
| p_avg_life_ind_cap_2 |
Value: 14 Type: Real (yr) Description: Controlled average life of industrial capital |
| p_avg_life_serv_cap_1 |
Value: 20 Type: Real (yr) Description: Default average life of service sector capital |
| p_avg_life_serv_cap_2 |
Value: 20 Type: Real (yr) Description: Controlled average life of service sector capital |
| p_fioa_cons_const_1 |
Value: 0.43 Type: Real Description: Default fraction of industrial output allocated to consumption |
| p_fioa_cons_const_2 |
Value: 0.43 Type: Real Description: Controlled fraction of industrial output allocated to consumption |
| p_ind_cap_out_ratio_1 |
Value: 3 Type: Real (yr) Description: Default industrial capital output ratio |
| p_land_yield_fact_1 |
Value: 1 Type: Real Description: Default land yield factor |
| p_nr_res_use_fact_1 |
Value: 1 Type: Real Description: Default non-recoverable resource utilization factor |
| p_ppoll_gen_fact_1 |
Value: 1 Type: Real Description: Default persistent pollution generation factor |
| p_serv_cap_out_ratio_1 |
Value: 1.0 Type: Real (yr) Description: Default fraction of service sector output ratio |
| p_serv_cap_out_ratio_2 |
Value: 1.0 Type: Real (yr) Description: Controlled fraction of service sector output ratio |
| pot_arable_land_tot |
Value: 3200000000.0 Type: Real (hectare) Description: Total potential arable land |
| ppoll_in_1970 |
Value: 136000000.0 Type: Real Description: Persistent pollution in 1970 |
| ppoll_trans_del |
Value: 20 Type: Real (yr) Description: Persistent pollution transmission delay |
| processing_loss |
Value: 0.1 Type: Real Description: Processing loss |
| reproductive_lifetime |
Value: 30.0 Type: Real (yr) Description: Reproductive life time |
| social_adj_del |
Value: 20 Type: Real (yr) Description: Social adjustment delay |
| social_discount |
Value: 0.07000000000000001 Type: Real (1/yr) Description: Social discount |
| subsist_food_pc |
Value: 230 Type: Real (kg/yr) Description: Available per capita food |
| tech_dev_del_TDD |
Value: 20 Type: Real (yr) Description: Technology development time |
| urb_ind_land_dev_time |
Value: 10 Type: Real (yr) Description: Urban and industrial land development time |
| t_air_poll_time |
Value: 4000 Type: Real (yr) Description: Air pollution change time |
| t_fcaor_time |
Value: 2002 Type: Real (yr) Description: Year of capital allocation to resource use efficiency |
| t_fert_cont_eff_time |
Value: 4000 Type: Real (yr) Description: Year of continued fertility change |
| t_ind_equil_time |
Value: 4000 Type: Real (yr) Description: Year of industrial equilibrium |
| t_land_life_time |
Value: 4000 Type: Real (yr) Description: Land life time |
| t_policy_year |
Value: 2002 Type: Real (yr) Description: Year of policy change |
| t_pop_equil_time |
Value: 4000 Type: Real (yr) Description: Population equilibrium time |
| t_zero_pop_grow_time |
Value: 4000 Type: Real (yr) Description: Time to zero population growth |
| p_fr_cap_al_obt_res_2 |
Value: {1, 0.1, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05} Type: Real[:] Description: Non-renewable resource fraction remaining |
| p_ppoll_tech_chg_mlt |
Value: {-0.04, -0.04, 0, 0} Type: Real[:] Description: Persistent pollution technology change multiplier |
| p_res_tech_chg_mlt |
Value: {0, 0, 0, 0} Type: Real[:] Description: Resource technology change multiplier |
| p_yield_tech_chg_mlt |
Value: {0, 0, 0.04, 0.04} Type: Real[:] Description: Yield technology change multiplier |
| agr_inp_init |
Value: 5000000000.0 Type: Real (dollar/yr) Description: Initial agricultural input |
| arable_land_init |
Value: 900000000.0 Type: Real (hectare) Description: Initial arable land |
| industrial_capital_init |
Value: 210000000000.0 Type: Real (dollar) Description: Initial industrial investment |
| labor_util_fr_del_init |
Value: 1 Type: Real Description: Initial delayed labor utilization fraction |
| land_fertility_init |
Value: 600 Type: Real (kg/(hectare.yr)) Description: Initial industrial investment |
| nr_resources_init |
Value: 2000000000000.0 Type: Real (ton) Description: Initial available non-recoverable resources |
| perc_food_ratio_init |
Value: 1 Type: Real Description: Initial perceived food ratio |
| pers_pollution_init |
Value: 25000000.0 Type: Real Description: Initial persistent pollution |
| pop1_init |
Value: 650000000.0 Type: Real Description: Initial population 14 years and younger |
| pop2_init |
Value: 700000000.0 Type: Real Description: Initial population 15 to 44 years old |
| pop3_init |
Value: 190000000.0 Type: Real Description: Initial population 45 to 64 years old |
| pop4_init |
Value: 60000000.0 Type: Real Description: Initial population 65 years and older |
| pot_arable_land_init |
Value: 2300000000.0 Type: Real (hectare) Description: Initial potential arable land |
| ppoll_tech_init |
Value: 1 Type: Real Description: Initial persistent pollution technology change factor |
| res_tech_init |
Value: 1 Type: Real Description: Initial non-recoverable resource technology factor |
| service_capital_init |
Value: 144000000000.0 Type: Real (dollar) Description: Initial service sector investment |
| urban_ind_land_init |
Value: 8200000.0 Type: Real (hectare) Description: Initial urban and industrial land |
| yield_tech_init |
Value: 1 Type: Real Description: Initial yield technology factor |
Outputs (16)
| population |
Type: Real Description: Total human world population |
|---|---|
| food |
Type: Real (dollar/yr) Description: Total annually produced food |
| industrial_output |
Type: Real (dollar/yr) Description: Total annual world industrial output |
| ppoll_index |
Type: Real Description: Persistent pollution index |
| nr_resources |
Type: Real Description: Remaining non-recoverable natural resources |
| fioa_ind |
Type: Real Description: Fraction of industrial output allocated to industrial/military complex |
| s_fioa_agr |
Type: Real Description: Fraction of industrial output allocated to food production |
| s_fioa_cons |
Type: Real Description: Fraction of industrial output allocated to consumption |
| s_fioa_serv |
Type: Real Description: Fraction of industrial output allocated to service sector |
| s_fr_cap_al_obt_res |
Type: Real Description: Fraction of capital allocated to resource use efficiency |
| life_expectancy |
Type: Real (yr) Description: Life expectancy |
| food_pc |
Type: Real (dollar/yr) Description: Total annual food per person |
| serv_out_pc |
Type: Real (dollar/yr) Description: Total annual services per person |
| ind_out_pc |
Type: Real (dollar/yr) Description: Total annual consumer goods per person |
| human_ecological_footprint |
Type: Real (Gha) Description: Human ecological footprint |
| human_welfare_index |
Type: Real Description: Human welfare index |
Components (13)
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Population_Dynamics1 |
Type: Population_Dynamics Description: Population dynamics |
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Pollution_Dynamics1 |
Type: Pollution_Dynamics Description: Persistent pollution generation |
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Arable_Land_Dynamics1 |
Type: Arable_Land_Dynamics Description: Arable land dynamics |
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Food_Production1 |
Type: Food_Production Description: Food production |
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Human_Ecological_Footprint1 |
Type: Human_Ecological_Footprint Description: Human ecological footprint |
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Human_Fertility1 |
Type: Human_Fertility Description: Human fertility |
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Human_Welfare_Index1 |
Type: Human_Welfare_Index Description: Human welfare index |
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Industrial_Investment1 |
Type: Industrial_Investment Description: Industrial investment |
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Labor_Utilization1 |
Type: Labor_Utilization Description: Labor utilization |
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Land_Fertility1 |
Type: Land_Fertility Description: Land fertility |
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Life_Expectancy1 |
Type: Life_Expectancy Description: Life expectancy |
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NR_Resource_Utilization1 |
Type: NR_Resource_Utilization Description: Non-recoverable natural resource utilization |
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Service_Sector_Investment1 |
Type: Service_Sector_Investment Description: Service sector investment |